Detailed Snap the metal coin inside the pack to activate, and the pack will be hot instant. resuable non-toxic handwarmer, heat pack CONTENTS:Sodium Acetate and water and PVC for outsideFUNCTION:Good to relieve minor muscle and rheumatic pains, joint pain.

Detailed Just softly click the metal plate inside then this Handwarmer will heat up to 53~55 degrees, work for 1~2 hours. CE, EN71 INSTRUCTIONS To activate: 1, Flex metal disc back and forth until crystals form.2.

Detailed Simply push up and down the metal plate inside then this handwarmer will heat up to 52-55 degrees, endlessly reusable. INSTRUCTION To activate: 1, Flex metal disc back and forth until crystals form.